ISSN:
1438-2385
Keywords:
Key words Yoghurt
;
Transglutaminase
;
Casein oligomerization
;
Gel-permeation chromatography
;
Isopeptides
Source:
Springer Online Journal Archives 1860-2000
Topics:
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract After pre-incubation of skim milk with microbial transglutaminase (10.5 U/100 ml skim milk or 3 U/g milk protein) at 40 °C for 150 min and subsequent heat inactivation, yoghurt was prepared. The breaking strength of this yoghurt increased in the given system from 550 cN to 920 cN with increasing pre-incubation time, reaching a plateau after 60 min. This increase in breaking strength correlates with a rather small amount of casein oligomerization, ranging from 10.9% to 25.8% using gel-permeation chromatography under reducing and denaturing conditions (sum of predominantly formed dimers and trimers in the total casein fraction). After enzymatic hydrolysis, N ε-(γ-glutamyl)-l-lysine was quantified by amino acid analysis. The isopeptide was formed exclusively intermolecularly, indicating that even a very small amount of casein crosslinking is capable of inducing significant changes in the functional properties of milk proteins.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002170050554
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